John a



(No Model.)

J. A. TOBIN.

comroumn STEEL ARMOR ANDMBTHOD 0F GONSTRUGTING THE SAME.

No. 351,297. Patented Oct. 19, 1886.

, 'UNITED STATES PATENT OFFICE.

JOHN A. TOBIN, OF WASHINGTON, DISTRICT OF COLUMBIA.

COMPOUND STEEL ARMOR AND METHOD OF CONSTRUCTING THE SAME.

SPECIFICATION forming part of Letters Patent No. 351,297, dated October 19, 1886.

Application filed August 24, 1886. Serial No. BILITB. (No model.)

.To all whom it may concern.-

Be it known that 1, JOHN A. TOBIN, a citizen of the United States, residing at \Vashington, in the District of Columbia, have invented a new and Improved Method in the Construction of Armor for Armor-Clad Ships.

WVhat I claim as my invention is an inn provement in the method of construction of compound steel armor for armor-clad ships, floating batteries, and forts, of which the following is a full, clear, and exact description.

The nature of the improvement and the manner in which the same is carried into effect may be readily understood by reference to the accompanying drawings.

Figure 1 represents a front and back plate of shipside armor. Fig. Zis a front and back plate of a turret. Fig. 3 is a cross-section showing deflect-ive side armor attached to ship side, Fig. 4, a quartersection of a conningtower, showing front and back plate; Fig. 5, a plan of a gunshield, showing the front and back plate. Fig. 6 is a cross-section through Fig. 1, atfg, showing cast bolt-holes It It in back plate for fastening side armor, also ribs m m on inside of plate I) to keep it intact when subjected to the impact of projectiles.

Similar letters of reference designate corresponding parts throughout the different figures.

The front and back plates only are shown in Figs. 1, 2, 4, 5, andG to illustrate my mode of constructing armor.

In the operation of accomplishing my said invention a pattern or templet one-quarter of the intended thickness of the armor is fashioned to suit the curvatures of the inside of the turret, conningtower, or side of the ship requiring protection, and from a back plateis cast in a green or dry sand mold lined with a refractory material, having sides and a bottom which form a part of the plate referred to. (See letter Z, Figs. 1, 2, 3, 4, and 5 in the accompanying drawings.) The outside plate, I), is molded from a pattern or templet having a thickness of about one-quarter of the finished plate, and may be so shaped as to suit any design of the exterior of any turret or armorplate. The steel used in plate 1) contains oer tain toughening substances and carbon in sufficient quantity to insure a tensile strength of about eighty tons per square inch. The caststeel plates a and b, after being joined together by a simple eontrivance, are heated in aheating-furnace until a white glowing heat is attained throughout the entire box or mold, the back and front plates of which compose the outside and inside of the armor. When the desired heat is obtained, the mold is withdrawn from the furnace and the cavity filled through its open top with molten steel, (having carbon in sufficient quantity to insure a tensile strength of about forty tons per square inch,) which fuses with the hard-steel face and mild-steel back plate, uniting the whole into a compound solid and inseparable mass.

In Figs. 1 and 3, It represents wood backing behind armor. By my method of construction conning-towers maybe made of solid inner and outer rings of any design and joined together in the manner described.

My improvement in the method of constructing compound steel armor for war-ships enables me to make with readiness, facility, and economy by casting, a large number of. either outside or inside turret or ship-side plates at the same time, also filling the cavities of several molds at one heat, thus rendering it, by this simple and economical process, unnecessary to occupy more than one furnace at any one time for the operation.

My defiective armor (see Fig. 3) having an inclined hard steel face to deflect and break up by impact the heaviest projectiles, a mildsteel back of great ductility (purified with manganese and other methods) to hold intact the steel composing the intermediate layer and the hard-steel face, all of which, from its irregular and peculiar shape, cannot be otherwise accomplished without the employment of a costly and extensive plant.

In my method of casting armor I may find it less expensive to make the plates 1), Figs. 1, 2, and 3, of a hard and tough quality of castiron, or I may prefer to make the face and back plates, a and Z), both of a mild quality of steel and fill the cavity 0 with a hard. tough quality of cast-iron or hard steel.

By my method of improvement in casting steel armor I may also find it economical and advantageous to add layers of steel of varying degrees of hardness to armor already in use by making a casting from apattern which will represent the exteriorof the turret or plate of the armor-clad, and after securing it heat the mass and fill the cavity with molten steel in the manner already described and set forth.

I am aware that heretofore compound armor for war-ships'and sea-coast defenses have been made by piling, rolling, and forging wrought-iron, which composes the back plate of the present compound armor in use; also,

that the thin hardstcel face composing the face of the armor is rolled from a hard-steel ingot, and that the space between them made by securing the two plates together is, after being heated in a furnace, filled with molten steel and the mass finally subjected to. the process of being rolled, hammered, and pressed into the desired shape by a costly and specially-adapted plant. I am also aware that armor constructed of steel has been cast from ingots for war-ships and subjected to the process of being rolled and pressed into the desired shapes; also, that cast-steel blocks or masses of uniform and varying degrees of hardness or temper have been broadly mentioned for ships side armor, and I am also aware of the construction and method of manufacture of armor-plates, as shown in the Patent No. 239,155, and English patents of Wilson, No. 4,746 of A. D. 1876, No. 3,472 of A. D. 1877, 'but I am not aware that my simple and expeditious method of constructing compound steel armor, as set forth and described, has ever been suggested or used by any one.

Having fully described my improved meth 0d of constructing compound steel armor, and the mode of carrying out my invention,I would state that in the foregoing description of my improved method of construction of cast-steel compound armor of varying degrees of hardness I have found it necessary,' for the purpose of distinctness, to refer to certain well known methods of operations as being adopted in the course of construction of my improved com;

pound steel armor-plate, and therefore I do not claim as my invention any of said methods of operation, except when employed in the construction of my improved compound cast steel armor-plate and ordnance in the manner heretofore described and set forth.

\Vhat I do consider as both novel and original in my improvement is not only the simplified and expeditious manner of effecting the operation as described and set forth by me for turrets, guns, gun-shields, con11ing-towe1's,and ships side armor, but also the fact that by construction and arrangement of the compound steel plate purified by ferro-manganese and other methods I secure a sounder and more reliable armor with a higher maximum of resistance to projectiles than can be secured by any other method of construction known to me. Finally, by my improved method of making armor I avoid altogether the useof costly and extensive plants, made necessary by hammering, rolling, and pressing large plates to give them the desired form.

\Vhat I claim as my invention is- 1. A compound steel armor-plate composed of a cast-steel back plate, of homogeneous mild steel molded to the proper form, with an inside-finished face of any particular shape, a hard faceplate of cast-steel molded and cast to any specific form, the two plates being connected and formed into a solid compound plate by an intermediate layer of molten steel of medium tensile strength, substantially as set forth.

2. The process of making a compound caststeel armor-plate, which consists in casting separately to any desired form a back plate of homogeneous mild steel and a hard-steel faceplate aud uniting the two plates with molten steel of medium tensile strength, as described.

JOHI\ A. TOBI'N.

Witnesses:

G120. W. RoUzER, TM. H. I-IARms. 

